How did scientist know prehistoric Indians existed if they didn't have a way to write things

What are the three criteria necessary to qualify for special education services under the individuals with disabilities education act category of intellectual disabilities? an intellectual functioning of 70 or more on a standardized iq test significant difficulty with tasks of everyday living (adaptive behavior) subaverage intellectual function (2 or more sd below the mean on a standardized iq test) impaired intellectual performance due to a traumatic brain injury deficits in intellectual functioning occur during the developmental period to distinguish id from other disabilities

Rank the following from most to least devasting: ordovician,permaian,cretaceous, pleistocene

Plz i need i really don’t want to fail i’m only 14. can somebody write a rough draft for me. about how tighter british control led to a revolution in colonial america has to be at least 4 paragraphs plz me passing depends on this plz